I've just got my Psi-Helmet from Sakharov after waiting 2 days and hunting zombified people around their mobile science labs for ammo loot.
The "defend the lab from several zombies waves" mission suddenly started before i got the Psi-Helmet, fortunately i had plenty of bullets (as i had prepared for the X-16 cleaning in order to shut down the Miracle Machine) so i decided to give a hand to the ecologists .
I went to pick up the item (it's used to resist the zombification that happen around the X-16 entrance) then went to war.
Along the ecologists troopers i destroyed lots of zombified stalkers.
Now i have a (modified) faction dynamic relationship addon, and as there was a lot of zombies being killed in all those waves, positive factions points were going fast (and they were near to be friends to my faction when i arrived at Yantar).
So much it reached a specific amount, and the modification done on the dynamic relationships addon adds a chance when relationship get too high to have a faction backstabbing you by declaring war (without that modification considering there's a lot of zombies and monolith troopers in that game that killing give positive points, every games would end with all the factions becoming your friend forever, ruining a part of the emergent gameplay that can be generated during that freeplay gameplay).
I didn't set the chance too high so super friendly factions would still get friendly (or turn neutral as there was a chance for this too) for a while, but i must have had very bad luck, because while i was near an ecologist friend gunning down a zombie, suddenly the guy turned to me and opened fire.
Good my duty radiation suit is strong (and full upgraded) as i managed to run to cover before being killed (and use some medi kit) as bullets started to rain around me from other ecologists still alive.
Yeah, the faction just turned on us, damn traitors
I decided to not try to kill all of them, because i wanted to keep enough medikits for the X-16 assault. So i ran into the Miracle Machine zone of influence (protected from being turned zombies by my nice shiny Psi-Helmet) and left the ex-friends new-enemies behind.
I finally approached the factory complex entrance (the entrance to the X-16 underground lab is in one of the buildings in the back of that complex).
Spotted a Chimera in one of the open area, the things also spotted me as it started to rush and
do their giant jumps around.
Fortunately staying behind the barriers i had nothing to worry, for a time at least, so i switched to my weapon under-barrel grenade launcher , from my position i would be able to land several grenades before the Chimera would find a way to claw me.
Then i suddenly heard a noise on my right, turned quickly to see a Pseudodog was jumping to my throat.
Not expecting this surprise attack from that sneaky beast i accidentally pressed the trigger.
The Pseudodog got exploded by the grenade.
Bad news considering the monster was so close, i exploded with him